Method and device for detecting corners

Abstract

Described is a computer-implemented method for determining material interfaces of an object from at least one measurement of the object, a rasterized representation of the object being produced by means of the measurement, the rasterized representation having a plurality of measurement points, a measurement point having at least one piece of image information, which indicates a value of a measurement variable for the object at the position of the measurement point. The method comprises the determining of a parameterization of the rasterized representation of the object, the parameterization assigning at least one parameter to each of the measurement points of a subset of the measurement points of the representation, and the applying of at least one parameter-dependent edge-detection operator to the measurement points of the rasterized representation, an edge-detection operator being designed to determine the location of at least one material interface in the rasterized representation.

It is claimed: 
     
       1. A computer-implemented method for determining material interfaces of an object from a rasterized representation of the object, the rasterized representation having a plurality of voxels corresponding to positions on the object, each of the voxels having at least one piece of image information which indicates a value of a measurement variable for the object at the position of the corresponding voxel, the method comprising:
 for each of a plurality of voxels, based upon at least two parameters specific to the respective voxel, defining an analysis direction parameter within the rasterized representation consisting of a direction within the rasterized representation of the object specific to the respective voxel; and 
 applying an edge-detection operator to the analysis direction parameters of the plurality of adjacent voxels, wherein the edge-detection operator determines a location of at least one material interface in the rasterized representation from the image information of at least one of the plurality of adjacent voxels and from the image information of least some of the voxels adjacent to the at least one voxel. 
 
     
     
       2. The method of  claim 1 ,
 wherein the image information of each voxel comprises at least one gray-scale value indicating the value of the measurement variable for the object at the position of the voxel, and 
 wherein the at least one edge-detection operator determines the location of the material interface by means of a fit of a theoretical model of the gray-scale values for a material interface to the curve of the gray-scale values of voxels in a vicinity of the selected voxel. 
 
     
     
       3. The method of  claim 2  wherein the edge-detection operator determines material interface locations from the fit along the analysis direction parameter. 
     
     
       4. The method of  claim 1  wherein rasterized presentation of the object is determined from a model of the object. 
     
     
       5. The method as claimed in  claim 4 , characterized in that the model is a CAD model. 
     
     
       6. The method of  claim 1  wherein the edge detection operator further determines a location of at least two directly adjacent material interfaces in the rasterized representation from an indication in the image information of at least one of the plurality of adjacent voxels that plural material interfaces are arranged directly adjacent to each other within the vicinity of the at least one voxel. 
     
     
       7. The method of  claim 1  wherein the analysis direction is perpendicular to the material interface to be determined. 
     
     
       8. A device comprising non-transitory computer program product having instructions executable by a computer, which when executed on a computer cause the computer to carry out a method for determining material interfaces of an object from a rasterized representation of the object, the rasterized representation having a plurality of voxels corresponding to positions on the object, each of the voxels having at least one piece of image information which indicates a value of a measurement variable for the object at the position of the corresponding voxel, the method comprising:
 for each of a plurality of voxels, based upon at least two parameters specific to the respective voxel, defining an analysis direction parameter within the rasterized representation consisting of a direction within the rasterized representation of the object specific to the respective voxel; and 
 applying an edge-detection operator to the analysis direction parameters of the plurality of adjacent voxels, wherein the edge-detection operator determines a location of at least one material interface in the rasterized representation from the image information of at least one of the plurality of adjacent voxels and from the image information of least some of the voxels adjacent to the at least one voxel. 
 
     
     
       9. The device of  claim 8  wherein the image information of each voxel comprises at least one gray-scale value indicating the value of the measurement variable for the object at the position of the voxel, and wherein the at least one edge-detection operator determines the location of the material interface by means of a fit of a theoretical model of the gray-scale values for a material interface to the curve of the gray-scale values of voxels in a vicinity of the selected voxel. 
     
     
       10. The device of  claim 9  wherein the edge-detection operator determines material interface locations from the fit along the analysis direction parameter. 
     
     
       11. The device of  claim 8  wherein rasterized presentation of the object is determined from a model of the object. 
     
     
       12. The device of  claim 11  wherein the model is a CAD model. 
     
     
       13. The device of  claim 8  wherein the edge detection operator further determines a location of at least two directly adjacent material interfaces in the rasterized representation from an indication in the image information of at least one of the plurality of adjacent voxels that plural of material interfaces are arranged directly adjacent to each other within the vicinity of the at least one voxel. 
     
     
       14. A computer-implemented method for determining material interfaces of an object from a rasterized representation of the object, the rasterized representation having a plurality of pixels corresponding to positions on the object, each of the pixels having at least one piece of image information which indicates a value of a measurement variable for the object at the position of the corresponding pixel, the method comprising:
 for each of a plurality of pixels, based upon at least two parameters specific to the respective pixel, defining an analysis direction parameter within the rasterized representation consisting of a direction within the rasterized representation of the object specific to the respective pixel; and 
 applying an edge-detection operator to the analysis direction parameters of the plurality of adjacent pixels, wherein the edge-detection operator determines a location of at least one material interface in the rasterized representation from the image information of at least one of the plurality of adjacent pixels and from the image information of least some of the pixels adjacent to the at least one pixel. 
 
     
     
       15. The method of  claim 14  wherein
 the image information of each pixel comprises at least one gray-scale value indicating the value of the measurement variable for the object at the position of the pixel, and 
 the at least one edge-detection operator determines the location of the material interface by means of a fit of a theoretical model of the gray-scale values for a material interface to the curve of the gray-scale values of pixels in a vicinity of the selected pixel. 
 
     
     
       16. The method of  claim 15  wherein the edge-detection operator determines material interface locations from the fit along the analysis direction parameter. 
     
     
       17. The method of  claim 14  wherein rasterized presentation of the object is determined from a model of the object. 
     
     
       18. The method of  claim 17  wherein the model is a CAD model. 
     
     
       19. The method of  claim 14  wherein the edge detection operator further determines a location of at least two directly adjacent material interfaces in the rasterized representation from an indication in the image information of at least one of the plurality of adjacent pixels that plural material interfaces are arranged directly adjacent to each other within the vicinity of the at least one pixel. 
     
     
       20. The method of  claim 14  wherein the analysis direction is perpendicular to the material interface to be determined. 
     
     
       21. A device comprising non-transitory computer program product having instructions executable by a computer, which when executed on a computer cause the computer to carry out a method for determining material interfaces of an object from a rasterized representation of the object, the rasterized representation having a plurality of pixels corresponding to positions on the object, each of the pixels having at least one piece of image information which indicates a value of a measurement variable for the object at the position of the corresponding pixel, the method comprising:
 for each of a plurality of pixels, based upon at least two parameters specific to the respective pixel, defining an analysis direction parameter within the rasterized representation consisting of a direction within the rasterized representation of the object specific to the respective pixel; and 
 applying an edge-detection operator to the analysis direction parameters of the plurality of adjacent pixels, wherein the edge-detection operator determines a location of at least one material interface in the rasterized representation from the image information of at least one of the plurality of adjacent pixels and from the image information of least some of the pixels adjacent to the at least one pixel. 
 
     
     
       22. The device of  claim 21  wherein the image information of each pixel comprises at least one gray-scale value indicating the value of the measurement variable for the object at the position of the pixel, and wherein the at least one edge-detection operator determines the location of the material interface by means of a fit of a theoretical model of the gray-scale values for a material interface to the curve of the gray-scale values of pixels in a vicinity of the selected pixel. 
     
     
       23. The device of  claim 22  wherein the edge-detection operator determines material interface locations from the fit along the analysis direction parameter. 
     
     
       24. The device of  claim 21  wherein rasterized presentation of the object is determined from a model of the object. 
     
     
       25. The device of  claim 24  wherein the model is a CAD model. 
     
     
       26. The device of  claim 21  wherein the edge detection operator further determines a location of at least two directly adjacent material interfaces in the rasterized representation from an indication in the image information of at least one of the plurality of adjacent pixels that plural of material interfaces are arranged directly adjacent to each other within the vicinity of the at least one pixel.